Tuesday, December 30, 2008

New Boiler and Hot Water Heating

I thought it worth while to put up a brief post on our upcoming hot water boiler replacement.

This is our current boiler:

The home inspector says it's probably around 85 years old. Maybe a bit younger than that. It has BTU ratings for coal, hard -stoked (Anthracite coal), and oil. It was converted to natural gas in 1983. The concrete block half-wall you can see behind the boiler conceals a large (12' x 3' diameter) abandoned oil tank. This was removed prior to closing and the floor and surrounding areas were tested for oil leaks (and came back clean thankfully).

Starting next week, our plumbers (who have been working on our supply and drain lines) will be switching over to getting the new boiler installed. It is a 93% efficient natural gas unit called the NTI-200. It is a condensing and modulating boiler, so it is very efficient and can adjust it's BTU output based on how much heat is needed (usually based on outdoor/indoor tempurature differential), rather than just having on/off modes.

The other nice thing about the new unit is that it will mount on the wall, taking up less space, vent to the outside via small PVC pipes, rather than taking up a chimney flue, and also heat our hot water. We'll be getting a 40 gallon indirect hot water tank. The boiler will heat the water through an indirect heat transfer method, and the water will be stored in the 40 gallon tank. If the hot water gets low, the boiler will fire up and make more, on-demand, up to 5.5 gallons/min, which means more or less infinite hot water. It is considered one of the most efficient methods to heat hot water. The current gas bill for the house is averaged at around $370/month (over the entire year). In addition to the new boiler, the 'extra' furnace in the old school rooms will be shut-down permanently, so we expect to save 30-50% of our gas bill (the 'extra' furnace is a really inefficient model).